Responding to President Bush's new smallpox-vaccination plan, Hospital Corpsman 2nd Class Jeremy West vaccinates a member of the smallpox response team at the National Naval Medical Center, in Bethesda, Md., on Dec. 19, 2002. (AFP Photo/Sybil McCarrol)

The worldwide eradication of smallpox — one of the most lethal diseases in history — stands alone in the annals of public-health successes. But since the Sept. 11 attacks, the prospect of terrorists using smallpox as a weapon has become a real possibility. Intelligence officials say enemies of the United States, including North Korea and Iraq, have obtained the killer virus. In December, President Bush announced sweeping plans to immediately begin vaccinating millions of soldiers and health-care workers, and then to make the vaccine available to the population at large, beginning in 2004. Many public-health experts say the president is taking the appropriate steps to protect the nation. But others warn that the vaccine is too dangerous to be given to millions of Americans when there is no immediate threat.